KR100552884B1 - Apparatus and method for mounting electronic part - Google Patents

Abstract

The present invention provides a mounting method that can be used for high density mounting, narrow pitch mounting, cavity mounting, and the like. In this method, the displacement amount with respect to the reference position of the chip held from the wafer by the pickup nozzle is obtained, and the displacement amount is corrected in consideration of the displacement amount when the chip is actually transferred to the mounting nozzle for mounting the chip on the substrate so that the mounting nozzle This always holds the chip in a constant posture.

Board, Chip, Mounting Nozzle, Pickup Nozzle, Displacement

Description

Apparatus and method for mounting electronic components {APPARATUS AND METHOD FOR MOUNTING ELECTRONIC PART}

Brief Description of the Drawings Figure 1 is a simplified illustration of the main structure of a mounting apparatus according to the invention.

2 shows a schematic structure of a mounting apparatus according to the invention.

3 is a flow chart used to explain the mounting method according to the present invention.

Fig. 4A shows the positional relationship between the chip, the pick-up nozzle and the mounting nozzle in the conventional mounting apparatus.

Fig. 4B shows the positional relationship between the chip, the pick-up nozzle and the mounting nozzle in the mounting apparatus according to the present invention.

5 is a perspective view showing a state of transfer of a chip between a pickup nozzle and a mounting nozzle after completing modifications to X, Y and θ displacements in the present invention;

<Explanation of symbols for the main parts of the drawings>

10: substrate table

11: substrate stage

13: X axis drive motor

15: Y axis drive motor

17: parts check camera

20: parts loading table

21: table

23: rotary drive motor

30: parts pickup

50: mounting part

51: mounting nozzle

The present invention relates to an apparatus and method for mounting an electronic component on a circuit board. In particular, the present invention relates to a mounting apparatus and a mounting method which are suitably used when an IC chip called a flip chip each including a bump (protruding electrode) is mounted on a circuit board.

In recent years, as electronic devices become smaller, it is required to mount electronic components more densely on a circuit board. In order to meet these demands, it is encouraged not only to reduce the pitch of the parts but also to increase the positioning accuracy during mounting. In addition, as a new form, a technique in which an electronic component is mounted in a cavity formed in a multilayer substrate is frequently employed.

Typically, in such a process of mounting an electronic component, an image processing technique is used as a method of improving the positioning accuracy when the electronic component is mounted on a circuit board. In particular, an image obtained by photographing an image of a circuit board in advance by a camera or the like is subjected to image processing to determine a position on which an electronic component is to be mounted. At the same time, the position where the electronic components arranged at the loading position are arranged is also determined through a similar process. These positions are then compared with each other to obtain a relative positional displacement. The electronic components arranged in the stowed position are picked up individually by the pick-up nozzle and temporarily placed on the intermediate stage. The electronic components are then individually held by the mounting nozzles. Then, after considering the positioning displacement, a process of mounting the electronic component using the mounting nozzle is executed.

When a chip such as an IC is mounted on a circuit board, the mounting head holding the chip contacts the chip at a predetermined position on the circuit board. Ultrasonic vibration is then applied to the associated chip via the mounting head to connect the chip to the circuit board. As narrow pitch is encouraged as described above, it is further required that the mounting nozzles will not obstruct the space around the location where the chip will be mounted. As a result, it is preferable that the shape of the chip gripping portion in the mounting nozzle matches the shape of the chip, and the size of the chip gripping portion is smaller than the size of the chip.

Moreover, it will be appreciated that even when the chip gripping portion is smaller in size than the chip and the shape coincides with the chip shape, the pick-up nozzle cannot adequately receive the chip from the component loading position. For example, as shown in Fig. 4A, the center position of the pickup nozzle is displaced by ΔX and ΔY in the X and Y axis directions with respect to the center of the chip, and the center axis of the pickup nozzle is angled by the angle Δθ with respect to the center axis of the chip. You can think of the displaced state. When only the positional relationship between the chip and the circuit board is known as in the related art, this positional displacement is often maintained even when the chip is transferred from the pickup nozzle to the mounting nozzle (mounting suction nozzle).

When the space between the chip to be mounted and the adjacent electronic component is narrow, if the chip is mounted in this state, the end of the mounting nozzle may interfere with and contact the electronic component. Moreover, as a mounting method recently adopted, there are cases where a chip is mounted on a circuit board so as to fit into a cavity formed in the circuit board. In this case, however, the end of the nozzle may protrude from the end of the chip, making itself impossible to fit. In addition, when the chip is bonded to the circuit board using ultrasonic waves, deflection or the like may occur when a load is applied to the chip, which may adversely affect the bonding state. As such, the positional displacement must be within acceptable levels for the current chip size or current mounting state. However, this positional displacement should preferably be improved in view of encouraging the increase in the narrower pitch and the like.

The present invention has been made in this respect, that is, an object of the present invention is to provide a chip holding apparatus and method which can hold a chip without causing the mounting nozzle to cause any positional displacement.

In order to achieve the above object, according to the present invention,

Picking up an electronic component located on the table by the pick-up nozzle;

Delivering the electronic component from the pick-up nozzle holding the electronic component to the mounting nozzle,

Comparing the position of the electronic component gripped by the mounting nozzle with the position on the circuit board on which the electronic component is mounted so as to modify the mounting position where the electronic component is mounted by the mounting nozzle;

Mounting the electronic component on the circuit board by a mounting nozzle, wherein the displacement of the electronic component gripped by the pick-up nozzle obtained in the form of displacement in the X and Y directions and rotation angle θ perpendicular to each other with respect to the reference position is detected. And a displacement of the X and Y directions and the rotation angle [theta] is modified to control the electronic component to have a predetermined posture with respect to the mounting nozzle when delivering the electronic component to the mounting nozzle.

According to the above-described mounting method, preferably one of the displacements in the X and Y directions is corrected by the movement of the pick-up nozzle, and the other of the displacements in the X and Y directions and the displacement of the rotation angle θ are actuated by the mounting nozzle. Is modified by

In addition, in order to achieve the above object,

A table that positions and grips electronic components and is capable of moving in the X and Y directions perpendicular to each other,

A pick-up nozzle that picks up an electronic component disposed on the table and is movable in the X direction;

Displacement amount detecting means for capturing an image of the electronic component held by the pick-up nozzle to detect the displacement of the electronic component with respect to the reference pose obtained in the form of displacements in the X and Y directions and the rotation angle θ perpendicular to each other;                         

A mounting nozzle for mounting an electronic component on a circuit board, the electronic component being delivered from the pick-up nozzle, capable of moving in the Y direction and rotating about an axis perpendicular to each of the X and Y directions;

A substrate stage for holding a circuit board,

When the electronic component is transferred from the pick-up nozzle to the mounting nozzle, the displacements in the X direction, Y direction and angle θ are modified to control the electronic component to have a predetermined posture with respect to the mounting nozzle. An apparatus for mounting a component is provided.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Fig. 1 shows a schematic structure of a main part in a mounting apparatus according to the present invention, and Fig. 2 briefly shows a schematic structure of a mounting apparatus. As shown in Fig. 2, the mounting apparatus includes a substrate table 10 for supporting a circuit board and the like, a component loading table 20 for supporting electronic components, a component pickup section 30 for supporting a pickup nozzle, It consists of a mounting part 50 which supports a mounting nozzle.

The substrate table 10 includes a substrate stage 11 that substantially supports the substrate by vacuum suction or the like, an X-axis drive motor 13 that drives the substrate stage 11 in the X-axis direction indicated by an arrow in the figure, and A part identification camera 17 for confirming the posture of the electronic component gripped by the mounting nozzle, which will be described later, and the Y-axis driving motor 15 for driving the substrate stage 11 in the Y-axis direction indicated by the arrow. camera). The part confirmation camera 17 is fixed to the substrate stage 11 and always has a constant positional relationship with the substrate stage 11.

The component stacking table 20 includes a table 21 on which components are to be arranged, a driving motor (not shown) for driving the table 21 in the X-axis and Y-axis directions, and a table 21 on the XY plane. Rotation drive motor 23 for rotating. The component placement substrate, which has almost the same shape as the wafer and is filled with electronic components such as, for example, flip chips, is fixed on the table 21 by vacuum suction or the like. These electronic components are only disposed on the component placement substrate, and thus can be easily picked up from the component placement substrate.

The component pickup unit 30 drives the pickup nozzle 33 which is rotatably supported with respect to the rotary shaft 31, the rotary shaft 31 and the pickup nozzle 33 to reverse the up and down direction of the chip. The pickup nozzle 33 includes a pickup nozzle lifting motor 35 for raising and lowering the pickup nozzle 33. These components are integrated with each other in the form of the pickup unit 39 and supported by the pickup base stage 37 to be driven in the X-axis direction by a drive motor (not shown). In addition, the component pickup unit 30 further includes a confirmation camera 41 and a pre-alignment camera 43 for confirming the loaded components. These components are fixed and supported by the base stage 37 separately from the unit 39 having the pickup nozzle 33 or the like.

The preliminary alignment camera 43 captures an image of the chip held by the component pickup nozzle 33. An image obtained through image capturing is image processed to obtain a displacement amount with respect to a reference posture or reference position when holding the chip. The displacement amount is obtained in the form of the displacement amount in the X axis direction, the displacement amount in the Y axis direction, and the angle θ. These displacement amounts are calculated by the controller (not shown) which constitutes a unit for detecting the displacement amount together with the preliminary alignment camera 43.

The mounting unit 50 is a mounting nozzle 51 having a function of mounting electronic components on a circuit board using, for example, ultrasonic waves, and θ for driving and rotating the mounting nozzle 51 about an axis perpendicular to the XY plane. The rotating motor 53 and the mounting nozzle raising and lowering motor 55 which raise and lower the motor 53 and the nozzle 51 are included. These components are integrated with each other in the form of a mounting unit 57 and supported by the mounting base stage 59 so that they can be driven in the Y-axis direction by a drive motor (not shown). The board | substrate mark confirmation camera 61 is fixed and supported by the mounting unit 57 separately from the mounting nozzle 51, the (theta) rotation motor 53, and the mounting nozzle lifting motor 55. As shown in FIG.

The driving of the components in the X-axis direction and the Y-axis direction consists of a combination of a ball screw shaft and a guide reel, etc., which are directly connected to the drive motor, respectively. Therefore, the description of these components is omitted here for the sake of simplicity. In addition, these components are known and these components can be suitably replaced by other known components, preferably depending on the required stopping precision and driving speed. Further, in this embodiment, the component pick-up nozzle is made to move in the X-axis direction, and the mounting nozzle is made to move in the Y-axis direction. However, the pick-up nozzle may be moved in the Y-axis direction, and the mounting nozzle may be moved in the X-axis direction.

Next, with reference to Figs. 1 and 3, which show flow charts useful for explaining a procedure for actually mounting an electronic component, the process of mounting the electronic component will be described in detail below. When the process for mounting the electronic component is started, first in step 1, the position of the electronic component such as the chip to be mounted on the substrate stage 11 is confirmed by the confirmation camera 41 for confirming the loaded component. do. Next, in the second step, the substrate stage 11 is driven in the X-axis and Y-axis directions so that the position at which the chip on which the chip to be mounted is arranged on the XY plane is to be picked up by the component pickup nozzle 33. Modified to match. In the third step, the component pick-up nozzle 33 is lowered to suck and hold the chip to be mounted.

In the fourth step, the component pick-up nozzle 33 holding the chip to be mounted is rotated about the rotation axis 31 to reverse the up and down direction of the chip to direct the chip upward. In step 5, the component pickup nozzle 33 is driven and moved in the X-axis direction to the position below the preliminary alignment camera 43. At this position, an image of the chip is taken. In step 6, the displacement amounts of X, Y and θ with respect to the predetermined reference pose of the associated chip are obtained based on the image photographing result. In step 7 after the displacement amount is detected, the component pick-up nozzle 33 holding the chip is moved to a position below the mounting nozzle 51 waiting at the chip transfer position in a state where the up and down direction of the chip is reversed.

Next, in step 9, the mounting nozzle 51 is lowered to contact the chip, and then the chip is sucked by vacuum suction or the like. Thereafter, the chip is released from a state such as vacuum suction by the component pick-up nozzle 33 and the chip transfer from the component pick-up nozzle 33 to the mounting nozzle 51 is terminated. In step 8 before the mounting nozzle 51 comes into contact with the chip, the arrangement (posture) of the mounting nozzle with respect to the chip is corrected in advance according to the displacement amount obtained in step 5. In particular, the displacement amount ΔX in the X-axis direction is corrected based on the drive of the component pickup nozzle 33 in the X-axis direction. In addition, the displacement amount ΔY in the Y-axis direction and the displacement amount Δθ in the chip rotation are corrected based on the driving of the mounting nozzle 51 in the Y-axis direction and the mounting nozzle 51 in the θ direction, respectively. As a result, the mounting nozzle 51 can always hold the chip in a predetermined posture.

5 is an enlarged perspective view schematically showing a specific example of the positional relationship between the mounting nozzle 51, the chip 2, and the component pickup nozzle 33. As shown in FIG. In the figure, the chip 2 has a substantially rectangular parallelepiped shape, and the upper surface of the chip 2 is sucked and held by the vacuum suction port 51a. In addition, the lower surface of the chip 2 has a bump adapted to bond to a circuit board, and is sucked and gripped by a vacuum suction port 33a provided to extend completely through the component pickup nozzle 33. As described below with reference to FIGS. 4A and 4B, the chip suction surface of the mounting nozzle 51 has a shape that is almost the same as or slightly smaller than the top surface of the chip 2. By implementing the present invention, it is possible for the chip suction surface of the mounting nozzle 51 to have the shape as shown in the figure.

In step 10 after the transfer of the chip to the mounting nozzle 51 is completed, the mounting nozzle 51 is driven in the Y-axis direction toward the circuit board. In step 11, the attitude of the chip is checked by the component identification camera 17 during driving. It should be noted that the substrate mark confirming camera 61 makes the imaging of the circuit board during the process and the detection of the chip mounting position based on the imaging results so far. In step 11, the posture of holding the chip is confirmed, and a positional relationship between the chip mounting position and the chip holding position is obtained to obtain a position displacement of the chip holding state with respect to the substrate mounting position again.

In step 12, the substrate stage 11 is driven in the X and Y axis directions so as to correct the circuit board displacement amounts in the X and Y axis directions obtained in step 11. The displacement amount is likely to be within the allowable range in step 8, but the displacement amount in the θ direction can be corrected again. However, this modification can be made again if necessary. Subsequently, in step 13, the mounting head 51 is lowered to the circuit board, and the process of press bonding and mounting the chip on the circuit board is performed to complete one mounting process.

In summary, the above flow is broadly classified into two processes, a first process and a second process, as described below. In the first process, the chips arranged at the position identified by the confirmation camera for confirming the loaded parts are picked up by the parts pick-up nozzle, the attitude of the chips held by the parts pick-up nozzle is detected by the preliminary alignment camera, The mounting nozzle is a step of holding the chip in a predetermined posture according to the detection result. The effects provided through this process will be described below with reference to FIGS. 4A and 4B. Fig. 4A shows a conventional case without preliminary alignment, and Fig. 4B shows a state in which the preliminary alignment of the present invention is performed. In both figures, the chip 2 observed from the chip 2 side is held by the head portion 33a of the component pickup nozzle 33, and the chip 2 viewed from the chip 2 side is mounted. The state gripped by the head part 51a of the nozzle 51 is shown.

In addition, in the drawing, the nozzle head portions 33a and 51a have suction ports 33b and 51b respectively used for vacuum suction. Since the mounting nozzle press-bonds the chip 2 to the circuit board (not shown), it is preferable that the mounting nozzle has a shape approximately equal to or slightly smaller than the suction surface of the chip. However, according to the conventional process, a situation may arise in which the side of the mounting nozzle 51 protrudes from the side of the chip 2, as shown in Fig. 4A. As shown in Fig. 4B, the chip is gripped by the mounting nozzle in such a state that all of the X-axis, Y-axis, and rotation angle θ of the mounting nozzle are all the same as the chip by performing the first process of preliminary alignment. Thus, even when the chips are arranged on a circuit board with a much narrower pitch than the conventional or when the chips are mounted in a cavity, the mounting nozzle provides a state where the chips are stably bonded to the substrate without disturbing other chips at all. It becomes possible to do it.

In the second process, the position and attitude of the chip held by the mounting nozzle are again confirmed, and the positional relationship between the position and attitude of the chip held by the mounting nozzle and the position on the circuit board on which the chip is to be mounted is obtained, and this position is obtained. After the relationship is considered, the chip is bonded to the circuit board. The chip 2 properly gripped by the mounting nozzle 51 undergoes a modification process again with respect to the bonding position, thereby allowing the chip to be mounted more accurately on the circuit board.

In the conventional mounting apparatus, such a transfer process has been adopted in which the process is performed once through the intermediate stage when the chip is transferred from the component pickup nozzle to the mounting nozzle for the purpose of shortening the mounting time. Also in the present invention, such an intermediate stage is provided and by adopting a structure in which the posture of the chip is detected in the intermediate stage, mounting can be effectively performed.

However, in order to achieve this, it is necessary to give the intermediate stage a function of driving in the X-axis and Y-axis directions, which complicates the device structure. In addition, intervening the intermediate stage may increase the number of transfers of the chip. With this increase, the amount of displacement of the attitude of the chip and the like increases more than when the chip is picked up. Considering the increase in the number of corrections or the number of correction parameters and the movement of the intermediate stage in the X- and Y-axis directions, the effect of shortening the mounting time is not significant when the positional relationship between the mounting nozzle and the chip is always kept constant. You can think of it.

In view of the foregoing, in the present invention, a mounting apparatus having a simpler structure without providing an intermediate stage can be constructed. As a result, the position correction when the mounting nozzle grips the chip and the position correction when the chip is mounted on the circuit board by the mounting nozzle are performed while the number of corrections of the shaft has a minimum number of times. For this reason, the mounting apparatus has a high reliability, and the adjustment at the initial stage of operation is easily performed. Therefore, it becomes possible to provide a mounting apparatus with high convenience.

Moreover, according to the present invention, between the conventional mounting process and the mounting process of the present invention, except that the process of detecting Δθ with the preliminary alignment camera and the process of correcting Δθ when the chip is transferred to the mounting nozzle are additionally included. There is not a big difference. As a result, by adding only the detection process and the modification process to the mounting apparatus used in the related art, the same effect can be achieved even for the mounting apparatus having various conveying systems. That is, even when a conventional mounting apparatus is used to carry out the present invention, narrow pitch mounting, cavity mounting, and the like can be performed without requiring high cost.

In this embodiment, it is assumed that a relatively small chip is mounted at a high density, but the present invention is not limited to this embodiment. In particular, when a relatively large electronic component is mounted, for example, the electronic component can be reliably gripped in a desired state by a mounting nozzle having an end face having a shape approximately equal to or slightly smaller than the associated electronic component. As a result, a uniform load can be applied to the entire end surface of the electronic component for mounting the electronic component, thereby achieving a good bonding state between the chip and the circuit board.

By practicing the present invention, even if a mounting nozzle having a suction end having a shape approximately equal to or slightly smaller than the chip is used, the end of the mounting nozzle does not protrude from the side of the chip when the mounting nozzle grips the chip. The chip can always be held in a constant position. As a result, even when high density mounting, narrow pitch mounting or cavity mounting is performed, the mounting nozzle can perform the mounting with high precision without disturbing other chips and circuit boards and the like.

Further, by implementing the present invention, when a load is applied to the chip by the mounting nozzle for mounting the chip on the circuit board, it is possible for the center of the suction end of the mounting nozzle to coincide with the center of the chip. As a result, the load applied to the chip from the mounting nozzle is always uniform over the entire bonding surface, so that a bonding state with high reliability and excellent precision is stably achieved.                     

Further, the present invention can be implemented by adding a process of detecting Δθ and a process of correcting Δθ when the chip is delivered to the mounting nozzle. As a result, a mounting apparatus having a simple conveying system conventionally used can be used instead, so that the present invention can be implemented at low cost.

Claims (3)

Picking up the electronic component located on the table by the pick-up nozzle, transferring the electronic component from the pick-up nozzle holding the electronic component to the mounting nozzle, and modifying the mounting position at which the electronic component is mounted by the mounting nozzle; A method of mounting an electronic component comprising comparing a position of an electronic component held by a mounting nozzle with a position on a circuit board on which the electronic component is mounted, and mounting the electronic component on the circuit board by the mounting nozzle, The mounting method comprises the steps of: detecting the displacement of the electronic component held by the pick-up nozzle with respect to the reference position, which is obtained in the form of displacement of the X and Y directions and the rotation angle θ perpendicular to each other; When delivering the electronic component to the mounting nozzle, modifying the displacement of the X and Y directions and the rotation angle θ to control the electronic component to have a predetermined attitude with respect to the mounting nozzle. A displacement according to claim 1, wherein one of the displacements in the X and Y directions is corrected by the movement of the pick-up nozzle, and the displacement of the rotation angle θ and the other of the displacements in the X and Y directions is corrected by the operation of the mounting nozzle. Electronic component mounting method, characterized in that. A device for mounting electronic components on a circuit board, A table that positions and grips electronic components and is capable of moving in the X and Y directions perpendicular to each other, A pick-up nozzle that picks up an electronic component disposed on the table and is movable in the X direction; Displacement amount detecting means for photographing an image of the electronic component held by the pick-up nozzle to detect the displacement of the electronic component with respect to the reference pose, obtained in the form of displacements in the X and Y directions and the angle θ perpendicular to each other; A mounting nozzle for mounting an electronic component on a circuit board, the electronic component being delivered from the pick-up nozzle, moving in the Y direction, and rotating about an axis perpendicular to each of the X and Y directions; A substrate stage for holding a circuit board, And when the electronic component is transferred from the pick-up nozzle to the mounting nozzle, the displacements in the X direction, Y direction and angle θ are modified to control the electronic component to have a predetermined attitude with respect to the mounting nozzle.

Images